As they waited for the jury`s verdict last week, they spoke of how unfair the criminal justice system seemed. Their father`s killer might go free, they said, because of things the jurors couldn`t hear, things just as damning as what they did hear.

Gall`s children knew what the jury did not--that their father had pointed Miller out; that one of Miller`s accomplices had named him as the killer; that Miller had a long history of violent crime and was not just the ``derelict``

his lawyer said he was.

``Why can`t the jury know all this?`` Gall`s son asked.

The answer lay in the Bill of Rights and rules of evidence it spawned to protect the accused`s right to a fair trial.

Those rules left prosecutors Nick Trutenko and Mary Ellen Cagney with one key witness: a convicted prostitute and admitted heroin addict.

She was Tamra Martin, 25, who testified that she set Gall up to be robbed. She said Gall had hired her as a prostitute and she planned to leave his door unlocked. Miller and a second man, Tiny Tim Gilbert, would sneak in and rob him. The old man, she said, was never supposed to know.

But things went wrong. Miller viciously attacked Gall, she said. She tried to pull him off, she said, then ran to Gilbert and pleaded with him to stop Miller.

It was too late. The old man`s nose, jaw and cheekbones were broken. Both his eyes were black and a foot-long bruise ran across his chest. He would die of the injuries several weeks after the beating he suffered on July 10, 1981. During closing arguments Thursday, Miller`s lawyer, public defender Richard Scholz, told the jury that Martin was a desperate prostitute trying to save herself by framing Miller in the death-penalty case.

``She sold herself to Mr. Gall,`` Scholz said. ``She sold herself to police officers. She sold herself to these authorities and now they`re asking you to buy what she`s selling . . .``

Gall`s children shuddered. They feared the jurors wouldn`t believe Martin, and Miller would go free.

``It must be difficult for them (Gall`s children) to understand the system, especially coming from the background they do,`` Scholz said after the trial. ``Lee Miller had the constitutional right to challenge the evidence against him, to have it brought before 12 people on a jury.``

Gall`s son and a police officer were at Gall`s side when the old man pointed to Miller`s picture. In some cases, a ``dying declaration`` is allowed as evidence because ``as a person approaches death, they have no reason to lie,`` Scholz said.

But such a declaration is admissible only if the victim knows that death is imminent and, in fact, does die soon. Gall lived for three weeks after the identification.

Scholz also argued that Gall`s identification may not have been reliable because of the 81-year-old Gall`s health.

Testimony from Gall`s son would have been only hearsay and would have deprived Miller`s lawyer of the right to cross-examine the man who actually made the identification.

Gall`s children couldn`t understand why Tiny Tim Gilbert wasn`t forced to face the jury. He earlier told police that he helped plan the robbery and that Miller killed Gall.

But Gilbert ``has the right not to be forced to make statements that could be used against him,`` Scholz said. ``He would have said, `I`ll take the 5th Amendment. I won`t say anything.``

The jury also knew nothing of Miller`s record. He had a conviction for attempted murder in 1976 and an armed robbery conviction in 1973, said Trutenko. In 1983, while free on bond in the Gall case, he was arrested and convicted of burglary in Indiana. He escaped from prison there, went to California and was arrested and convicted of a sexual assault and robbery.

``Why don`t they tell the jury this?`` Gall`s son asked. But a past criminal record cannot be used as evidence unless the defendant takes the witness stand, because it would unfairly bias the jurors against a defendant who is presumed innocent until proved guilty. A criminal background can be used only to help determine the credibility, not the guilt, of a witness.

Miller didn`t take the stand. As far as the jury knew, he was a 35-year-old ``derelict`` who lived at 3434 N. Broadway when Gall was beaten in his apartment at 7403 N. Ridge Blvd.

The lawyers` closing arguments covered the sparse circumstantial evidence but centered on Martin.

``Tamra Martin is trying to avoid the death penalty. . . . She has every reason in the world to lie,`` Scholz told the jury. ``Please don`t buy what Tamra Martin has to say. Please.``

Cagney didn`t argue that Martin was a prostitute and drug addict. ``She made her own life,`` the prosecutor said. ``She made a botch of it, didn`t she?`` But Martin was not a killer, Cagney argued--she took the witness stand to tell the truth.

Throughout the trial, Cagney and Trutenko used only the evidence allowed by Criminal Court Judge Thomas Fitzgerald. ``They tried one of the most honorable cases I`ve seen,`` Scholz said, ``and did it under difficult circumstances.``

Before they went back to the jury room, Cagney told the jurors, ``The truth is always the strongest argument. You can try to chip away at it, but it stands tall.``

The jurors were out for two hours. They came back with the verdict:

guilty. Gall`s daughter cried tears of relief, and his son smiled. Maybe this country`s justice system isn`t so bad after all, they said.